The isolation and characterization of lysozyme from human foetal membranes: a comparison with the enzyme from other sources.

Lysozyme (muramidase) was isolated from an acidic extract of human foetal membranes by adsorption and elution from octadecyl silica. It was further purified by gel-filtration and ion-exchange. The final product was homogeneous by high performance liquid chromatography (h.p.l.c.) and electrophoresis. It was indistinguishable from human milk lysozyme by all criteria investigated, including amino acid composition, electrophoretic mobility, retention time on h.p.l.c. and sequence of the first nine residues. Human uterine decidual tissue was shown to contain a similar concentration of lysozyme to foetal membranes. The enzyme was also present at lower concentrations in amnion, placenta and amniotic fluid.